“across，through”这两个词大致上有什么区别 ？谢谢

through, across和over的区别
①、through：穿过
I threw it through the window.
Is it quicker to drive round the town, or straight though the centre?
②、across: from one side to the other
（在平面上）越过，在/到……对/面，横过。
I can’t swim across the river.
我不能游到河对岸。
He went across the hall to the door.
他越过大厅到门口。
③、over: 翻越过
across和over两者都表示从一侧向另一侧的运动：
She drove over /across the bridge.
但如果越过的是一个高的物体，则用over:
He climbed over the wall.
如果越过的是一个平面，则宜用across：
He went across the hall to the door.
across和through都表示“穿过”，“通过”的意思，across表示从物体表面“穿过”、“通过”;而through则表示从内部“穿过”、“通过”。
by 的用法

介词，表示通过…方法或途径的意思，译成“靠，通过”，后面可加名词或名词短语。

e.g. 1) The house was destroyed by fire. 房屋被火烧毁了。

2) travel by air /land/sea. 航空（陆路，航海）旅行

3) go by train /boat/ bus 乘火车（船，公共汽车）去

4) shake sb. by the hand 和某人握手

5) I study English by watching English movies. 我通过看英文电影学英语。